Allow libc++ to use modules in C++03.
Allow libc++ to use modules in C++03.

Libc++ internal uses <atomic> in C++03 code but the module map forbids its use.
This causes the libc++ 'std' module to fail to build in C++03.

This patch removes the requirement to fix this issue.


git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@287693 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx